1. Field of the Invention
The invention relates to a photosensitive polymer and a resist composition containing the polymer. More particularly, the invention relates to a fluorinated photosensitive polymer and a resist composition containing the fluorinated polymer.
2. Description of the Related Art
As the manufacture of semiconductor devices becomes more complicated and the integration density of the resulting semiconductor devices increases, there continues to be a need to form fine patterns during the manufacturing process. Furthermore, with regard to 1-Gigabit or greater capacity semiconductor memory devices, pattern imaging processes capable of resolving features for design rules of 0.2 μm or less are needed. Conventional photoresist materials exposed with a KrF excimer laser (248 nm) are limited in their ability to form such fine patterns. For this reason, developing lithography techniques have focused on using shorter wavelength exposure light sources such as an ArF excimer laser (193 nm). Although lithography techniques using an ArF excimer laser may permit patterning of 100 nm features, resolving features with more demanding size requirements will tend to require even shorter wavelength exposure light sources and new lithography techniques that can utilize such exposure sources. One such exposure source is the F2 excimer laser (157 nm) which may be capable of forming 70 nm patterns, resulting in efforts to formulate suitable resist materials.
Conventional F2 excimer laser resists include a copolymer of t-butyl trifluoromethylacrylate and hexafluoroisopropanol substituted styrene, represented by formula I below, or a copolymer of tetrafluoroethylene and norbornene disclosed by DuPont, represented by formula II below:
